I started my first pension when I was 32 as I spent all my money previous to that on flying lessons. I couldn't contribute much for the first few years as I was earning circa 20k PA as a TP F.O.
In my mid 30s I realised the problem I am facing and have spent the last 10 years trying to catch up. Currently I contribute 25% of my salary (circa 65k PA) and my employer contributes 9%.
I'm hoping to have a pension of about 40k PA in today's money when I retire. That will have to support myself and my partner who has been child rearing for the last 10 years and had low paid jobs before that.
My advice; don't do it this way.